Spectroscopic module

ABSTRACT

The spectroscopy module  1  is provided with a body portion  2  for transmitting light L 1 , L 2 , a spectroscopic portion  3  for dispersing light L 1  made incident from the front plane  2   a  of the body portion  2  into the body portion  2  to reflect the light on the front plane  2   a , a light detecting element  4  having a light detecting portion  41  for detecting the light L 2  dispersed and reflected by the spectroscopic portion  3  and electrically connected to a wiring  9  formed on the front plane  2   a  of the body portion  2  by face-down bonding, and an underfill material  12  filled in the body portion  2  side of the light detecting element  4  to transmit the light L 1 , L 2 . The light detecting element  4  is provided with a light-passing hole  42  through which the light L 1  advancing into the spectroscopic portion  3  passes, and a light incident opening  42   a  of the light-passing hole  42  is partially covered by a light transmitting plate  16.

TECHNICAL FIELD

The present invention relates to a spectroscopy module for dispersing light to detect the light.

BACKGROUND ART

As conventional spectroscopy modules, there are known, for example, those disclosed in Patent Documents 1 and 2. Patent Document 1 has disclosed a spectroscopy module which is provided with a light-transmitting supporting body, an incident slit portion which makes light incident into the supporting body, a concave diffraction grating for dispersing the light made incident into the supporting body to reflect the light, and a diode for detecting the light dispersed and reflected by the concave diffraction grating.

Patent Document 1: Japanese Published Unexamined Patent Application No. H04-294223

Patent Document 2: Japanese Published Unexamined Patent Application No. 2004-354176

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

Nevertheless, in the spectroscopy module described in patent document 1, upon attachment of the incident slit portion and the diode to the supporting body, there is a fear that a relative positional relationship between the incident slit portion and the diode may deviate, thus resulting in a decrease in reliability of the spectroscopy module.

Now, the present invention has been made in view of the above situation, an object of which is to provide a highly reliable spectroscopy module.

Means for Solving the Problems

In order to attain the above object, the spectroscopy module of the present invention is provided with a light-transmitting body portion, a spectroscopic portion for dispersing light made incident from a predetermined plane of the body portion into the body portion to reflect the light on the predetermined plane, a light detecting element having a light detecting portion for detecting the light dispersed and reflected by the spectroscopic portion and electrically connected to wiring formed on the predetermined plane by face-down bonding, an underfill material filled in the body portion side of the light detecting element and capable of transmitting the light, in which the light detecting element is provided with a light passing hole through which the light advancing to the spectroscopic portion passes and a light incident opening of the light passing hole is partially covered by a light transmitting plate.

In the spectroscopy module, a light passing hole through which light advancing to the spectroscopic portion passes and a light detecting portion for detecting light dispersed and reflected by the spectroscopic portion are formed at the light detecting element. Therefore, it is possible to prevent the deviation of the relative positional relationship between the light passing hole and the light detecting portion. Further, the light detecting element is electrically connected to wiring formed on the predetermined plane of the body portion by face-down bonding, and a light-transmitting underfill material is filled in the body portion side of the light detecting element. Therefore, the body portion and the light detecting element can be improved in mechanical strength, and light which advances between the body portion and the light detecting element can also be adjusted for the refraction index. Further, a light incident opening of the light passing hole is partially covered by a light transmitting plate. Thereby, a part which is not covered by the light transmitting plate is given as an outgassing portion, the underfill material enters into the light passing hole, and the surface of the light incident side of the underfill material is given as an approximately flat plane inside the light passing hole. Therefore, light can be appropriately made incident into the body portion. As a result, according to the spectroscopy module, it is possible to improve the reliability.

In the spectroscopy module of the present invention, it is preferable that the light passing hole is formed in such a manner that the light incident opening includes the light outgoing opening of the light passing hole when viewed from the center line thereof and the light transmitting plate partially covers the light incident opening so as to include the light outgoing opening when viewed from the center line. According to the above constitution, light made outgoing from the light outgoing opening of the light passing hole is to pass through the light transmitting plate and the surface of the light incident side of the underfill material which is given as an approximately flat plane by the light transmitting plate, by which the light can be appropriately made incident into the body portion.

In the spectroscopy module of the present invention, it is preferable that the wiring has a light absorbing layer on a predetermined plane. For example, where the wiring is directly formed on the predetermined plane of the body portion in order to attach the wiring to the body portion more firmly, thereby preventing the wiring from breaking or the like, the light absorbing layer can be used to prevent stray light from being reflected in a diffused manner due to the wiring.

In the spectroscopy module of the present invention, it is preferable that there is formed on the predetermined plane the light absorbing layer having a first light passing portion through which light advancing to the spectroscopic portion passes and a second light passing portion through which light advancing to the light detecting portion passes. In this instance, the light absorbing layer acts to suppress the generation of stray light and also absorb the stray light, thus making it possible to suppress the stray light from being made incident into the light detecting portion of the light detecting element.

Further, the spectroscopy module of the present invention is provided with a light-transmitting body portion, a spectroscopic portion for dispersing light made incident from a predetermined plane of the body portion into the body portion to reflect the light on the predetermined plane, a light detecting element having a light detecting portion for detecting the light dispersed and reflected by the spectroscopic portion and electrically connected to wiring formed on the predetermined plane by face-down bonding, and an underfill material filled in the body portion side of the light detecting element and capable of transmitting the light, in which the light detecting element is provided with a light passing hole through which the light advancing into the spectroscopic portion passes.

EFFECT OF THE INVENTION

According to the present invention, it is possible to improve the reliability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a spectroscopy module of one embodiment of the present invention.

FIG. 2 is a cross sectional view of the spectroscopy module taken along line II to II given in FIG. 1.

FIG. 3 is an enlarged plan view showing the vicinity of a light passing hole of the spectroscopy module given in FIG. 1.

FIG. 4 is an enlarged cross sectional view showing the vicinity of the light passing hole of the spectroscopy module given in FIG. 1.

DESCRIPTION OF REFERENCE NUMERALS

-   1: spectroscopy module -   2: body portion -   2 a: front plane (predetermined plane) -   3: spectroscopic portion -   4: light detecting element -   6: light absorbing layer -   6 a: light passing portion (first light passing portion) -   6 b: light passing portion (second light passing portion) -   9: wiring -   9 d: light absorbing layer -   12: underfill material -   16: light transmitting plate -   41: light detecting portion -   42: light passing hole -   42 a: light incident opening -   42 b: light outgoing opening -   CL: center line

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, a detailed description will be given for preferred embodiments of the present invention by referring to the drawings. It is noted that in the individual drawings, the same reference letters or numerals are given to the same and corresponding parts, with overlapping description omitted.

FIG. 1 is a plan view of a spectroscopy module of one embodiment of the present invention. FIG. 2 is a cross sectional view of the spectroscopy module taken along line II to II given in FIG. 1. As shown in FIG. 1 and FIG. 2, the spectroscopy module 1 is provided with a light-transmitting body portion 2, a spectroscopic portion 3 for dispersing light L1 made incident from a front plane (predetermined plane) 2 a of the body portion 2 into the body portion 2 to reflect the light on the front plane 2 a side, and a light detecting element 4 for detecting light L2 dispersed and reflected by the spectroscopic portion 3. The spectroscopy module 1 is to disperse the light L1 to a plurality of lights L2 by the spectroscopic portion 3 and detect the light L2 by the light detecting element 4, thereby measuring the wavelength distribution of the light L1 and the intensity of a specific wavelength component or the like.

The body portion 2 is provided with a light-transmitting member 2 ₁ formed in a rectangular plate shape by using light-transmitting glass or a light-transmitting resin such as BK7, Pyrex (registered trade mark) or quartz and a light-transmitting member 2 ₂ formed at a predetermined position on the rear plane of the light-transmitting member 2 ₁. The light-transmitting member 2 ₂ is formed by using the same material as that of the light-transmitting member 2 ₁, that is, a light-transmitting organic-inorganic hybrid material or light-transmitting low-melting temperature glass for replica molding in a predetermined shape (in this instance, a shape in which a hemispherical lens is cut out by two planes approximately orthogonal to the flat plane portion thereof and also approximately in parallel to each other to give the side planes), thereby acting as a lens for forming an image on a light detecting portion 41 of the light detecting element 4 on the basis of light L2 dispersed and reflected by the spectroscopic portion 3. The light-transmitting member 2 ₂ is arranged so that the side planes are approximately in parallel with the longitudinal direction of the light-transmitting member 2 ₁ and bonded to the light-transmitting member 2 ₁ with an optical resin or by direct bonding where it is made with the same material as that of the light-transmitting member 2 ₁.

The spectroscopic portion 3 is a reflection type grating having a diffracting layer 14 formed on the outer surface of the light-transmitting member 2 ₂ and a reflecting layer 5 formed on the outer surface of the diffracting layer 14. The diffracting layer 14 is a serrated cross-sectional blazed grating, a rectangular cross-sectional binary grating, a sinusoidal cross-sectional holographic grating or the like. The diffracting layer 14 is formed, for example, by coating a photosensitive resin on the outer surface of the light-transmitting member 2 ₂ and then using a light-transmitting mold (grating mold) made of quartz or the like to subject the photosensitive resin to UV curing. The diffracting layer 14 is made more stable when heated and cured after the UV curing. The reflecting layer 5 is formed, for example, in a film shape by evaporating Al, Au or the like on the outer surface of the diffracting layer 14. Further, a protective layer made with SiO₂, MgF₂ or the like may be formed on the reflecting layer 5. It is noted that materials of the diffracting layer 14 shall not be limited to photosensitive resins but may include photosensitive glass, photosensitive organic-inorganic hybrid materials, heat-deformable resins/glass and organic-inorganic hybrid materials.

The light detecting element 4 is provided with a light detecting portion 41 in which long photodiodes are arrayed one-dimensionally in a direction approximately orthogonal to the longitudinal direction thereof to detect light L2 dispersed and reflected by the spectroscopic portion 3 and a light passing hole 42 which is installed together with the light detecting portion 41 in a direction at which the photodiodes are arrayed one dimensionally and through which light L1 advancing to the spectroscopic portion 3 passes. The light passing hole 42 is a slit extending in a direction approximately orthogonal to the longitudinal direction of the light-transmitting member 2 ₁ and formed by etching, blasting or laser processing in a state that it is positioned at a high accuracy with respect to the light detecting portion 41. The light detecting element 4 is arranged in such a manner that a direction at which the photodiodes are arrayed one dimensionally is approximately in agreement with the longitudinal direction of the light-transmitting member 2 ₁ and also the light detecting portion 41 turns to the front plane 2 a of the body portion 2. It is noted that the light detecting element 4 shall not be limited to the photodiode array but may include a C-MOS image sensor, a CCD image sensor or the like.

On the front plane 2 a (more specifically, the front plane of the light-transmitting member 2 ₁) of the body portion 2, there is formed a wiring 9 made of a single film of Al, Au or the like or a laminated film of Ti—Pt—Au, Ti—Ni—Au, Cr—Au or the like. The wiring 9 is provided with a plurality of pad portions 9 a arranged at the center of the light-transmitting member 2 ₁, a plurality of pad portions 9 b arranged at the end of the light-transmitting member 2 ₁ in the longitudinal direction and a plurality of connection portions 9 c for connecting the corresponding pad portions 9 a and the pad portions 9 b. Further, the wiring 9 is provided on the front plane 2 a of the body portion 2 with a light absorbing layer 9 d made of a single film of CrO or the like or a laminated film of Cr—CrO or the like.

Further, on the front plane 2 a of the body portion 2, there is formed a light absorbing layer 6 so as to expose the pad portions 9 a, 9 b of the wiring 9 and also cover the connection portions 9 c of the wiring 9. The light absorbing layer 6 is provided with a light passing portion (first light passing portion) 6 a through which light L1 advancing to the spectroscopic portion 3 passes and a light passing portion (second light passing portion) 6 b through which light L2 advancing to the light detecting portion 41 of the light detecting element 4 passes. The light passing portion 6 a is a slit extending in a direction approximately orthogonal to the longitudinal direction of the light-transmitting member 2 ₁. The light absorbing layer 6 is subjected to a predetermined-shaped patterning and formed integrally by using CrO, a CrO-containing laminated film, black resist or the like.

An external terminal of the light detecting element 4 is electrically connected to the pad portion 9 a exposed from the light absorbing layer 6 by face-down bonding via a bump 15 so that the light passing hole 42 opposes the light passing portion 6 a of the light absorbing layer 6 and the light detecting portion 41 also opposes the light passing portion 6 b of the light absorbing layer 6. Further, a flexible printed board 11 for taking out an output signal of the light detecting element 4 is electrically connected by wire bonding to the pad portions 9 b exposed from the light absorbing layer 6. Then, an underfill material 12 for transmitting light L1, L2 is filled in the body portion 2 side (in this instance, between the light detecting element 4 and the light-transmitting member 2 ₁ or the light absorbing layer 6) of the light detecting element 4. It is noted that a light incident opening of the light passing hole 42 is partially covered by the light transmitting plate 16 fixed to the front plane of the light detecting element 4.

FIG. 3 is an enlarged plan view showing the vicinity of the light passing hole of the spectroscopy module given in FIG. 1. FIG. 4 is an enlarged cross sectional view showing the vicinity of the light passing hole of the spectroscopy module given in FIG. 1. As shown in FIG. 3 and FIG. 4, the light passing hole 42 is provided with a light incident-side portion 42 ₁ for demarcating a light incident opening 42 a from which light L1 is made incident and a light outgoing-side portion 42 ₂ for demarcating a light outgoing opening 42 b from which light L1 is made outgoing. The light outgoing-side portion 42 ₂ is formed in a rectangular solid shape extending in a direction approximately orthogonal to the longitudinal direction of the light-transmitting member 2 ₁ and the light incident-side portion 42 ₁ is formed in a square pyramid shape widening from the light outgoing-side portion 42 ₂ to the opposite direction. More specifically, the light passing hole 42 is formed in such a manner that the light incident opening 42 a includes the light outgoing opening 42 b, when viewed from the center line (CL) thereof.

The light transmitting plate 16 is formed in a rectangular thin-plate shape by using light-transmitting glass or the like, covering partially a light incident opening 42 a, while there is left a marginal part along the longitudinal direction of the light incident opening 42 a, so as to include the light outgoing opening 42 when viewed from the center line (CL) of the light passing hole 42. A marginal part of the light incident opening 42 a which is not covered by the light transmitting plate 16 is given as an outgassing portion, and the underfill material 12 enters into the light passing hole 42 when filled, thereby, the surface 12 a of the light incident side of the underfill material 12 is given as an approximately flat plane inside the light passing hole 42. It is noted that the light transmitting plate 16 may partially cover the light incident opening 42 a, while there is left a marginal part along a direction approximately orthogonal to the longitudinal direction of the light incident opening 42 a left.

In the above-constituted spectroscopy module 1, light L1 is made incident from the front plane 2 a of the body portion 2 into the body portion 2 via the light transmitting plate 16, the light passing hole 42 of the light detecting element 4 and the light passing portion 6 a of the light absorbing layer 6, advancing inside the light-transmitting members 2 ₁, 2 ₂ and arriving at the spectroscopic portion 3.

The light L1 which has arrived at the spectroscopic portion 3 is dispersed into a plurality of light L2 by the spectroscopic portion 3. The thus dispersed light L2 is reflected by the spectroscopic portion 3 on the front plane 2 a side of the body portion 2, advancing inside the light-transmitting members 2 ₂, 2 ₁, and arriving at the light detecting portion 41 of the light detecting element 4 via the light passing portion 6 b of the light absorbing layer 6. The light L2 which has arrived at the light detecting portion 41 is detected by the light detecting element 4.

As so far described, in the spectroscopy module 1, the light passing hole 42 through which light L1 advancing to the spectroscopic portion 3 passes and the light detecting portion 41 for detecting light L2 dispersed and reflected by the spectroscopic portion 3 are formed at the light detecting element 4 in a state that they are positioned from each other at a high accuracy. It becomes unnecessary to install different members for forming the light passing hole 42 and to position between the light passing hole 42 and the light detecting portion 41 (more specifically, only the spectroscopic portion 3 is positioned with respect to the light detecting element 4). Therefore, it is possible to downsize the spectroscopy module 1 at a reduced cost.

Further, in the spectroscopy module 1, the light detecting element 4 is electrically connected to the wiring 9 formed on the front plane 2 a side of the body portion 2 by face-down bonding, and an underfill material 12 for transmitting light L1, L2 is filled in the body portion 2 side of the light detecting element 4. As described so far, such a constitution is provided that the light detecting element 4 is electrically connected externally via the wiring 9 formed at the body portion 2. Thereby, for example, in a case where a flexible printed board 11 is directly (mechanically) connected to the light detecting element 4, a force applied to the flexible printed board 11 at the point of using the spectroscopy module 1 is not directly transferred to the light detecting element 4, thus making it possible to prevent the light detecting element 4 from receiving loads such as stress and also downsizing the light detecting element 4. Further, the underfill material 12 is filled in the body portion 2 side of the light detecting element 4, by which the body portion 2 and the light detecting element 4 can be improved in mechanical strength. It is also possible to adjust the refraction index on all channels through which light L1, L2 advancing between the body portion 2 and the light detecting element 4 pass.

Further, in the spectroscopy module 1, the light passing hole 42 is formed so that the light incident opening 42 a includes the light outgoing opening 42 b when viewed from the center line (CL), and the light transmitting plate 16 covers partially the light incident opening 42 a so as to include the light outgoing opening 42 b when viewed from the center line (CL). Thereby, a part which is not covered by the light transmitting plate 16 is given as an outgassing portion, an underfill material 12 enters into the light passing hole 42, and the surface 12 a of the light incident side of the underfill material 12 is given as an approximately flat plane inside the light passing hole 42. Then, light L1 made outgoing from the light outgoing opening 42 b is to pass through the light transmitting plate 16 and the surface 12 a of the light incident side of the underfill material 12 which is given as an approximately flat plane by the light transmitting plate 16. Therefore, the light L1 can be appropriately made incident into the body portion 2.

Further, in the spectroscopy module 1, the wiring 9 is provided with a light absorbing layer 9 d on the front plane 2 a side of the body portion 2. Thereby, the wiring 9 is attached to the body portion 2 more firmly to prevent the wiring 9 from breaking or the like. Thus, even if the wiring 9 is formed directly on the front plane 2 a of the body portion 2, the light absorbing layer 9 d can be used to prevent stray light from being reflected in a diffused manner due to the wiring 9.

Still further, in the spectroscopy module 1, there is formed on the front plane 2 a of the body portion 2 the light absorbing layer 6 having a light passing portion 6 a through which light L1 advancing to the spectroscopic portion 3 passes and a light passing portion 6 b through which light L2 advancing to the light detecting portion 41 of the light detecting element 4 passes. The light absorbing layer 6 is used to suppress the generation of stray light and also absorb the stray light, thus making it possible to suppress the stray light from being made incident into the light detecting portion 41.

The present invention shall not be limited to the above-described embodiment.

For example, the light absorbing layer 6 may be formed on the front plane 2 a of the body portion 2, and the wiring 9 may be formed on the front plane of the light absorbing layer 6. In this instance, even if the wiring 9 is not provided on the light absorbing layer 9 d, it is possible to prevent stray light from being reflected in a diffused manner due to the wiring 9.

Further, the light-transmitting member 2 ₂, which acts as a lens, may be formed integrally with the diffracting layer 14 by using light-transmitting low-melting-point glass for replica molding or the like. In this instance, it is possible to simplify the production process and also prevent the deviation of the relative positional relationship between the light-transmitting member 2 ₂ and the diffracting layer 14.

INDUSTRIAL APPLICABILITY

According to the present invention, it is possible to improve the reliability. 

1. A spectroscopy module comprising: a light-transmitting body portion; a spectroscopic portion for dispersing light made incident from a predetermined plane of the body portion into the body portion to reflect the light on the predetermined plane; a light detecting element having a light detecting portion for detecting the light dispersed and reflected by the spectroscopic portion and electrically connected to wiring formed on the predetermined plane by face-down bonding; and an underfill material filled in the body portion side of the light detecting element and capable of transmitting the light; wherein the light detecting element is provided with a light passing hole through which the light advancing into the spectroscopic portion passes, and a light incident opening of the light passing hole is partially covered by a light transmitting plate.
 2. The spectroscopy module as set forth in claim 1, wherein the light passing hole is formed in such a manner that the light incident opening includes a light outgoing opening of the light passing hole when viewed from the center line thereof, and the light transmitting plate covers a part of the light incident opening so as to include the light outgoing opening when viewed from the center line.
 3. The spectroscopy module as set forth in either claim 1, wherein the wiring is provided with a light absorbing layer on the predetermined plane.
 4. The spectroscopy module as set forth in claim 1, wherein a light absorbing layer having a first light passing portion through which the light advancing into the spectroscopic portion passes and a second light passing portion through which the light advancing into the light detecting portion passes is formed on the predetermined plane.
 5. A spectroscopy module comprising: a light-transmitting body portion; a spectroscopic portion for dispersing light made incident from a predetermined plane of the body portion into the body portion to reflect the light on the predetermined plane; a light detecting element having a light detecting portion for detecting the light dispersed and reflected by the spectroscopic portion and electrically connected to wiring formed on the predetermined plane by face-down bonding; and an underfill material filled in the body portion side of the light detecting element and capable of transmitting the light; wherein the light detecting element is provided with a light passing hole through which the light advancing into the spectroscopic portion passes. 